The present invention relates in general to high speed communications equipment and, more particularly, to small hubs or mini-hubs which do not require external power cabling, take up less space than existing hubs and, in the case of managed mini-hubs, can be controlled directly via a computer""s system bus without requiring a separate RS-232, Ethernet or other communication/control connection. While the present invention is generally applicable to high speed communications equipment, it will be described herein with reference to Fibre Channel (FC) and FibreXtreme (FX) (a trademark of Systran Corporation, assignee of the present application) data link equipment for which it is particularly applicable and initially being used. The description will refer to either of these systems by the term Fibre Channel even though FX uses a protocol that is a modification of the standard FC protocol.
Commercially available FC hubs are implemented in rack mounted boxes that require external power cabling and communication/control connections in the case of managed hubs. These hubs are not well suited for use in embedded, real-time, military/defense and industrial applications where equipment must be small, requires minimum cabling and low power levels, can be easily xe2x80x9cruggedizedxe2x80x9d and provides low latency. Computer systems used in these applications are typically implemented in VERSAmodule Eurocard (VME) and Compact Peripheral Computer Interconnect (CompactPCI) formats.
Currently available managed hubs require some type of connection to a computer that monitors status and controls the configuration of the hub. Today""s hubs typically use an RS-232 or Ethernet connection to achieve the monitoring/control connections.
Monitoring and control of a hub over a serial connection, such as RS-232 or Ethernet, requires software overhead to assemble communication packets and additional hardware to serialize/deserialize the packets. Additionally, such hubs are only able to support Arbitrated Loop topologies.
There is, thus, a need for improved Fibre Channel hubs for use in embedded, real-time, military/defense and industrial applications that do not require a separate source of power or a separate control connection. Preferably, such hubs would be able to support topologies in addition to Arbitrated Loop including, for example, topologies such as Point-to-Point, One to Many (broadcast) or loop segmenting (where ports can be grouped into separate independent loops).
This need is met by the invention of the present application wherein mini-hubs comprising a wide variety of configurations can be produced in small form factors to provide FC and FX type hubs with a limited number of ports, for example four (4) to eight (8) ports. The mini-hubs of the present invention provide compact, low cost hubs for form factors that can include, without limitation, PCI Mezzanine Card (PMC), CompactPCI, and VME. The mini-hubs of the present invention are easily installed into an unused system slot of a host computer or as a mezzanine card for use in the host computer. Thus, mini-hubs of the present invention use system power received directly from the backplane of the host computer so that no external power cabling connections are required and mechanical support is provided by the system chassis or carrier card into which a mini-hub is installed. With the mini-hubs of the present invention, external RS-232 or Ethernet communication/control cabling is eliminated altogether since for managed mini-hubs the system bus of the host computer, for example a VME, CompactPCI or PCM bus, is used to communicate with the managed mini-hub. This direct communication also reduces system latency. In this way, the mini-hubs meet the cabling, power, ruggedization, and low latency requirements required in embedded, real-time, military/defense and industrial applications.